Darwin was ridiculed in his time for suggesting that small land animals could have transformed into modern whales, like the young sperm whale seen above in the waters off the Caribbean island of Dominica. (See pictures of some of the species that inspired Darwin.)

Whales "have a long generation time, and they don't have huge populations. They're like the worst-case scenario for trying to evolve structures rapidly," Luskin said. "To fix all the mutations needed to convert a little land mammal into a fully functional whale [in ten million years]--mathematically that's totally not possible."